1. Field of the Invention
The present invention relates to a method of manufacturing a color filter used for a color liquid crystal display cell and a device of the same, specially to a method of manufacturing a color filter that will not generate a transfer displacement and a device of manufacturing the same.
2. Description of the Related Art
FIG. 9 is a schematic illustration of a conventional laser irradiation device 7. And, FIG. 10 is a graph to illustrate a relation between the irradiation width of laser beams radiated from the laser irradiation device 7 and the energy density (intensity) thereof.
The laser irradiation device 7 as shown in FIG. 9 includes a laser oscillator 8 in which semiconductor devices are incorporated, and a single axis laser beam radiated from an outgoing beam aperture 8a of this laser oscillator 8 is reflected by mirrors 9a, 9b, and 9c in this order, and guided to an irradiation point P.
By using this type of the laser irradiation device 7, laser beams are irradiated on a color film sheet 50, as shown in FIG. 6, which is disposed on a color transfer support of a glass substrate or the like, whereby a color filter is formed.
The color film sheet 50 includes a base film 3, photothermal conversion layer 4, and color ink layer 2, which are laminated in this order. The base film 3 employs a drawn resin of a polyethylene terephthalate (PET) or the like. The photothermal conversion layer 4 employs a mixture of a resin binder and a carbon powder, which has the property to absorb light and convert it into heat. The color ink layer 2 employs a resin binder with a pigment added thereto, which assumes one of the three kinds of colors, R (red), G (green), and B (blue).
The foregoing color film sheet 50 is disposed in a tight contact on a color transfer support 1 shown in FIG. 6, laser beams are irradiated locally from above the base film 3, and the color ink layer 2 is transferred onto the color transfer support 1.
FIG. 11 illustrates a moving device 60 to move the color transfer support 1. This moving device 60 moves a part on which the color transfer support 1 is placed, and the laser irradiation device 7 is used always in a fixed state.
The moving device 60 is comprised of a support mount 62, a substrate absorbing plate 61, and a linear motor driving unit 66. Further, the linear motor driving unit 66 includes a coil body 63, a slide yoke 64, and a magnet 65. The substrate absorbing plate 61 is placed on the support mount 62, and the color transfer support 1 is absorbed and fixed on the substrate absorbing plate 61, while in use. And, the coil body 63 is a coil for a linear motor, in which a coil 63a is wound up on a bobbin. The upper sides of jaws 63b, 63c projected on both ends of the coil body 63 are fixed on the lower sides of the support mount 62.
In order to operate the moving device 60, controlling the direction of a magnetic force of the magnet 65 induces a force that acts on the coil body 63 in the sliding direction, and the force thereby moves the color transfer support 1 in a X direction, accompanied with the support mount 62.
Though not illustrated, a linear motor driving unit having the similar mechanism to the foregoing is provided on both the ends of the moving device 60, in order to move the entire body of the moving device 60 in a Y direction.
However, when the laser irradiation device 7 as shown in FIG. 9 is used, optical components (mirrors) intervening between the outgoing beam aperture 8a of the laser oscillator 8 and the irradiation point P are assembled and adjusted by a single optical axis; and therefore, not only the productivity is low, but also there has been created an abnormality of edges in the transfer pattern to the color transfer support 1 by the color ink layer 2, which is a problem.
That is, as recognized from the graph illustrated in FIG. 10, a displacement of the irradiation point P causes a difference in the intensity of the laser beams. Concretely, the graph shown in FIG. 10 is called as the Gaussian distribution, the intensity becomes highest at the center position C of the laser beams, and the intensity is s sharply weakened as the irradiation point is displaced from the center position C. In particular, to the color ink layer 2 transferred to the color transfer support 1, the laser beams are irradiated within the transfer width (irradiation width) L that is illustrated by the two dotted lines in FIG. 10, and the intensity at the edges become lowest within the transfer width L. Accordingly, the color ink layer 2 cannot be melted sufficiently at the edges, the intensity differences at the boundaries become high as well, the boundaries become unclear, and there has been created an abnormality of the edges in the transfer pattern.
On the other hand, when the moving device 60 as shown in FIG. 11 is used, a heat generated from the coil body 63 is transferred from the support mount 62 to the substrate absorbing plate 61, and further to the color transfer support 1; and thereby, there has been created an abnormality in the transfer accuracy of the color filter.
That is, a heat generated from the coil body 63 heats the color transfer support 1, which generates a temperature gradient on the surface of the color film sheet 50 disposed on the color transfer support 1. Thereby, the temperature of the center of the color transfer support 1 becomes high, whereby, the elongation of the center of the color transfer support 1 becomes large as compared to the other part thereof. When a transfer is conducted while the elongation is generated, the color filter (color ink layer 2) has created a displacement in the pitch thereof when the temperature reduces to a normal and the elongation is reduced to the original state.
The extent of displacement in the pitch becomes about 0.8 .mu.m, when the temperature gradient of 1 degree per 100 mm is given. In practice, since there is the temperature difference of about 10 degree between the center of the color transfer support 1 and the edge thereof, there has been created an error of about 8 .mu.m. In manufacturing the foregoing color filter, the pitch has to be arranged within the allowance of .+-.3 .mu.m, and the foregoing moving device 60 can exceed this error range, which created a problem.